Accumulative sliding construction method of segmental track-changing for unequal-span structure

ABSTRACT

Provided is an accumulative sliding construction method of segmental track-changing for unequal-span structure, which divides the unequal-span structure into at least two sliding sections according to span variation, and a plurality of track segments corresponding to the spans of each sliding section. By providing sliders on the main truss/beam of each sliding section at positions corresponding to the track segments that each main truss/beam need to pass through, the sliding section smoothly passes through the sliding track segments to be in position; in addition, the main truss/beam of each sliding section is provided with temporary lengthening auxiliary structure or divided into an initial-mounted unit and rear-mounted units to allow the main truss/beam of each sliding section to pass through the track segments smoothly and to be in place.

CROSS REFERENCE TO RELATED APPLICATION

This application claims priority to PCT Application No.PCT/CN2020/077990, having a filing date of Mar. 5, 2020, the entirecontents of which are hereby incorporated by reference.

FIELD OF TECHNOLOGY

The following relates to a sliding construction method by hydraulicthruster, in particular to an accumulative sliding construction methodof segmental track-changing for unequal-span structure.

BACKGROUND

The degree of mechanization, automation and informatization ofconstruction is one of the important indicators of the level of buildingconstruction technology in a country or region. Compared with thelabor-intensive and extensive construction mode of traditional buildingproduction, mechanized construction is an effective way to improveengineering quality and reduce labor costs. For example, forconstruction environment with limited horizontal transportation orlimited installation and utilization of hoisting machinery or verticaltransportation equipment, accumulative sliding installation technologyis often used for steel structure construction, which can greatlyimprove the construction environment, the construction efficiency,construction quality, and safety, and shorten the construction periodwith lower engineering cost.

However, the existing accumulative sliding construction methods mostlyapply to regular structures. Traditional accumulative slidingconstruction technology is not applicable for unequal-span structure, asthe sliding track couldn't match various intervals of the sliding shoesor the sliders arranged on each sliding main truss/beam. Consideringabove defects, extensive, labor-intensive and low-tech construction modesuch as high-altitude spread operation method is still used for currentconstruction of unequal-span steel structure, which is time-consumingand laborious, and not easy to ensure the construction quality andsafety.

The prosperous construction market in China has become the largestconstruction market in the world due to the rapid development of socialeconomy and the acceleration of urbanization. With the improvement ofpeople's material life, the pursuit of spiritual and cultural life andthe improvement of aesthetic taste, higher requirements are also putforward for the modeling and artistic expression of buildings. A largenumber of buildings present unequal-span, complex structural forms.Thus, a new mechanized sliding construction technology is proposed andstudied in order to transform the large-scale, labor-intensive andextensive backward construction production mode in China.

SUMMARY OF INVENTION

An aspect relates to an accumulative sliding construction method ofsegmental track-changing for unequal-span structure. The applicationsolves the sliding construction problem of the unequal-span structurewith large span alteration.

The present application discloses an accumulative sliding constructionmethod of segmental track-changing for unequal-span structure, which issuitable for unequal-span structure including at least three maintrusses/beams with different spans, and the construction methodcomprises the following steps:

Step 1, designing a sliding track; dividing the unequal-span structureinto at least two sliding sections and an individual truss/beamaccording to structural span variation, wherein each sliding sectioncomprises a sliding main truss/beam and a set of secondary trusses/beamsconnected;

the sliding track is designed into a plurality of parallel tracksegments, the number of the track segments is equal to the number of thesliding zone blocks, each track segment is offset from the adjacenttrack segment by a certain distance, and the certain distance isrespectively corresponding to the span differentials between every twoadjacent main trusses/beams;

Step 2, analyzing the sliding process of the unequal-span structure; theweight of the sliding structure and the track layout, the specification,quantity and layout of the sliding hydraulic thrusters are determined;

Step 3, installing the track segments and an assembly platform;installing the track segments are arranged according to the design ofStep 1, and the assembly platform used to assemble the structure ismounted to a first track segment, wherein the first track segmentextends onto the assembly platform;

Step 4, sliding process begins; a first main truss/beam assembled on theassembly platform, and pushed away from the assembly platform by a setof hydraulic thrusters, wherein at least one assembled temporaryauxiliary device for anti-overturning is arranged for preventing thefirst main truss/beam from overturning during the sliding process;

after the first main truss/beam leaving the assembly platform, a secondmain truss/beam is assembled on the assembly platform, and at least oneset of secondary trusses/beams between the sliding main truss/beam andthe second main truss/beam to form a first sliding section, then theassembled temporary auxiliary device for anti-overturning is detached;

Step 5, track-changing process; pushing the sliding section and thesecond main truss/beam in the fourth step 4 forward by the hydraulicthrusters until the first main truss/beam reaches a position where thefirst track segment and its adjacent track segment, a second tracksegment overlaps;

due to different track gauges of the track segments, each maintruss/beam is provided with at least one slider at positionscorresponding to track gauges of the track segments that the maintruss/beam slides through ensuring the main truss/beam leaves the firsttrack segment and slides on the second track segment to perform atrack-changing process.

According to one aspect of the construction method of the presentapplication, as the span of the main truss/beam is smaller than thetrack gauge of the track segment which it engages with, the both ends ofmain truss/beam are attached with assembled temporary lengtheningauxiliary structure. The span of the main truss/beam is enlarged to thetrack gauge between the track segments for engaging with the tracksegments.

According to an aspect of the construction method of the presentapplication, the assembled temporary lengthening auxiliary structureincludes a plurality of sub-units, the length of each sub-unit isdetermined by the differential of the track gauges between two adjacenttrack segments of the track segments.

According to an aspect of the construction method of the presentapplication, as the sliding main truss/beam passes one of the tracksegments, the sub-units corresponding to the one of the track segmentsare removed.

According to an aspect of the construction method of the presentapplication, as the span of the main truss/beam is larger than the trackgauge of the track segment which the main truss/beam engages with, themain truss/beam is divided into the initial sliding unit and therear-mounted units which that are installed at both ends of the initialsliding unit, wherein the span of the initial sliding unit is equal tothe track gauge of the track segment. Therefore, the initial slidingunit smoothly slides at the first track segments.

According to an aspect of the construction method of the presentapplication, the rear-mounted units comprise a plurality of sub-units,the length of each sub-unit corresponding to differences in track gaugesof two adjacent track segments of the track segments, as the maintruss/beam passes one of the track segments and switches to anothertrack segment with different track gauge, the subsequent sub-units areassembled so that the spans thereof are adapted to slide on thesubsequent track segments.

According to an aspect of the construction method of the presentapplication as the sliding main truss/beam passes one of the tracksegments, the sub-units corresponding to the next one of the tracksegments could be mounted so as to continue the sliding process on thesubsequent track segments.

According to an aspect of the construction method of the presentapplication folding hinges are used for mounting the rear-mounted unitto the initial unit, as well as connection between sub-units of therear-mounted units, and as the sliding main truss/beam passes one of thetrack segments, the sub-units corresponding to the next one of the tracksegments are unfolded. Thus, all the rear-mounted units are installedinitially, and the corresponding sub-units are opened when the tracksegments are switched.

According to an aspect of the construction method of the presentapplication, the connections between the main truss/beam and theassembled temporary lengthening auxiliary structure, the connectionsbetween the initial sliding unit and the rear-mounted unit, theconnections between the sub-units of the assembled temporary lengtheningauxiliary structure, and the connections between the sub-units of therear-mounted unit are formed by channel steels and high strength bolts,which facilitates the installation.

According to an aspect of the construction method of the presentapplication, in Step 4 of the construction method, before pushing thefirst main truss/beam to slide, the assembled temporary auxiliary devicefor anti-overturning is arranged in the front and rear of the first maintruss/beam.

The assembled temporary auxiliary device for anti-overturning isL-shaped or triangular welded by section steel or steel plate. One endof the assembled temporary auxiliary device for anti-overturning istemporarily fixed with the main truss/beam through bolts, and the otherend of the assembled temporary auxiliary device for anti-overturning isarranged on the sliding track segments. Sliders are arranged between theassembled temporary auxiliary device for anti-overturning and thesliding track segments ensure the relative sliding smoothness betweenthe two. The first set of hydraulic thrusters is mounted on the maintruss/beam and propels the sliding main truss/beam to a predeterminedposition.

According to an aspect of the construction method of the presentapplication, In order to the facilitation of the track-changing process,the prior track segments and the subsequent track segments could beprovided with export free cuts and import free cuts, respectively, sothat the sliding structure could switch between the track segments withdifferent track gauges to continue to slide. As mentioned above, thelength of the overlap of two adjacent track segments is long enough forremoving and installing the hydraulic thrusters on the prior andsubsequent track segments.

The segmental track-changing cumulative sliding construction method ofunequal-span structure of the present application, not only solves theengineering problem that the traditional accumulative slidingconstruction method is difficult to implement on unequal-span structure,but also effectively alter the extensive, labor-intensive andlow-technology-level construction mode that the unequal-span steelstructure construction still largely adopts, such as the high-altitudebulk method and the like. The method overcomes the defects ofconstruction method of the structure, such as time-consuming,labor-consuming, as well as the difficulty to guarantee the constructionquality and safety. The mechanization and automation of construction isimproved, and the construction period and cost are saved.

BRIEF DESCRIPTION OF DRAWINGS

The present disclosure will be described hereinafter in details withreference to the figures and the embodiments, obviously, the figures tobe described below are merely embodiments of the present disclosure. Forthose skilled in the art, other figures may be obtained according tothese figures without any creative work.

FIG. 1 is a schematic plan view of unequal-span structure according tothe first embodiment of the present disclosure;

FIG. 2 is a schematic diagram illustrating layout of a sliding track andequipment system according to the first embodiment of the presentdisclosure;

FIG. 3 is a schematic diagram of a first main truss/beam prepared forassembly according to the first embodiment of the present disclosure;

FIG. 4 is a schematic diagram illustrating the track-changing processaccording to the first embodiment of the present disclosure;

FIG. 5 is a further schematic diagram illustrating a track-changingprocess according to the first embodiment of the present disclosure;

FIG. 6 is a further schematic diagram illustrating the track-changingprocess according to the first embodiment of the present disclosure;

FIG. 7 is a schematic diagram illustrating the process of accumulativesliding construction of segmental track-changing according to the firstembodiment of the present disclosure after being completed;

FIG. 8 is a schematic diagram of the sliding main truss/beam with anassembled temporary lengthening auxiliary structure according to thefirst embodiment of the present disclosure;

FIG. 9 is a detail drawing illustrating connection of the assembledtemporary lengthening auxiliary structure according to the firstembodiment of the present disclosure;

FIG. 10 is a cross sectional view of FIG. 9 along A-A;

FIG. 11 is a detail drawing of an assembled temporary auxiliary devicefor anti-overturning according to the present disclosure;

FIG. 12 is a cross sectional view of FIG. 11 along B-B;

FIG. 13 is a detail drawing of structure of a slider according to thepresent disclosure;

FIG. 14 is a detail drawing of a connection between the slider and thesliding main truss/beam according to the present disclosure;

FIG. 15 is a schematic diagram of arrangement of sliding track andequipment according to the second embodiment of the present disclosure;

FIG. 16 is a schematic diagram of a first main truss/beam prepared forassembly according to the second embodiment of the present disclosure;

FIG. 17 is a schematic diagram of the track-changing process accordingto the second embodiment of the present disclosure;

FIG. 18 is a further schematic diagram of the track-changing processaccording to the second embodiment of the present disclosure;

FIG. 19 is a further schematic diagram of the track-changing processaccording to the second embodiment of the present disclosure;

FIG. 20 is a schematic diagram illustrating the process of accumulativesliding construction of segmental track-changing according to the secondembodiment of the present disclosure after being completed;

FIG. 21 is a schematic diagram illustrating division of an initialsliding unit and its rear-mounted units according to the secondembodiment of the present disclosure;

FIG. 22 is a schematic diagram of the folding connection of the initialsliding unit and the rear-mounted units according to the secondembodiment of the present disclosure;

FIG. 23 is a schematic diagram illustrating an unfolded state of theinitial sliding unit and the rear-mounted unit according to the secondembodiment of the present disclosure.

DETAILED DESCRIPTION OF EMBODIMENTS

In order that the objectives, technical solutions, and advantages of thepresent disclosure will become more apparent, specific embodiments ofthe present disclosure will be further described with reference to theaccompanying drawings.

Embodiment 1

Embodiment 1 of the present application is shown in FIGS. 1-14.

FIG. 1 illustrates a typical roof or floor of unequal-span structureincluding four main trusses/beams 21, 22, 23, 24, of different spans andthree sets of secondary trusses/beams, 31, 32, 33, wherein every twoadjacent main trusses/beams are connected by a set of secondarytrusses/beams, and the whole structure is supported on structuralcolumns 1.

When the sliding construction of the unequal-span structure is carriedout by sliding from a side with larger-span to a side of smaller-spandue to restriction of construction site conditions, the method ofsegmental track-changing for unequal-span structure includes thefollowing steps.

(1) The sliding track is designed and arranged. As shown in FIG. 2,considering safety and economic factors, the unequal-span structure isdivided into three sliding sections and a fourth truss/beam could beinstalled directly at the end according to the shape and size theunequal-span structure and the arrangement, wherein each sliding sectionincludes a main truss/beam and a set of secondary trusses/beamsconnected.

According to the division of the unequal-span structure, the slidingtrack is divided into three track segments 61, 62 and 63 with differenttrack gauges. The track gauge of each track segment corresponds to thespan of a sliding section, and the distances that each track segmentoffsets from its adjacent track segment in the span direction is shownas L1, L2, respectively.

(2) Based on the analysis of the whole process of accumulative sliding,the weight of the sliding structure and the track layout, thespecification, quantity and layout of the sliding hydraulic thrusters71, 72, 73 and 74 are determined, as shown in FIG. 2.

(3) The track segments and assembly platform are installed. As shown inFIG. 3 and FIG. 11, the track beam 17, the track beam supportingstructure 4, as well as the track segments 61, 62 and 63 are installedaccording to the design of step (1). And an assembly platform 8 used toassemble the structure is mounted on the track segments with largertrack gauge, in this embodiment, namely the assembly platform 8 isinstalled on the track segment 63. After being assembled, the maintruss/beam may leave the assembly platform 8 to slide along the tracksegment, so that the assembly platform 8 could be used for assemblingthe next main truss/beam, and the secondary truss/beam between the twomain trusses/beams can be installed to form the sliding section of themain truss/beam left on the assembly platform 8. The rest parts could beassembled and mounted in a similar way.

The track segment 63 may extend onto the assembly platform as desired,as shown in FIG. 3.

(4) The sliding process begins. As shown in FIGS. 3-5 and 8, After beingassembled on the assembly platform 8, the first main truss/beam 21 isattached with assembled temporary lengthening auxiliary structure 212 onboth ends for engaging with the track segments 63, as the length of thefirst main truss/beam 21 is less than the track gauge of the tracksegments 63.

The first set of hydraulic thrusters 71 could be installed on the firstmain truss/beam 21 after the installation of the first main truss/beam21 and the assembled temporary lengthening auxiliary structure 212, andthen the first set of hydraulic thrusters 71 controlled by a computercontrol system is employed to push the first main truss/beam 21 totravel along the track segments 63.

(5) Track-changing process begins: track-changing process is requiredwhen the sliding structure, for example the first main truss/beam 21 isswitched between the track segments due to different track gauges oftrack segments 61-63.

As shown in FIGS. 9 and 10, wherein FIG. 10 is a sectional view takenalong A-A in FIG. 9. The sliding process of each main truss/beam isanalyzed and the tracks that each main truss/beam successively slidesthrough are determined, then sliders 91 could be arranged atcorresponding positions of the main truss/beam and/or the assembledtemporary lengthening auxiliary structure 212 for the track-changingprocess between the track segments with different track gauges. Takingthe first main truss/beam 21 as an example:

1. The first main truss/beam 21, which is of the minimum span length,needs to slide through all three track segments 63, 62 and 61 insequence. As shown in FIG. 8, at least one assembled temporarylengthening auxiliary structure 212 is provided at both ends of thefirst main truss/beam 21 to allow the first main truss/beam 21 to slidethrough the track segments 63, 62, whose track gauge is greater than thespan of the first main truss/beam 21. The assembled temporarylengthening auxiliary structures 212 are temporarily connected to lowerchord 211 of the first main truss/beam 21 via channel steels 10 byhigh-strength bolts 111 and 112 respectively.

The length of the assembled temporary lengthening auxiliary structure212 is determined by differentials of the track gauges of the tracksegments 61, 62 and 63, which is shown as L1+L2 in FIG. 2. For the sakeof the facilitation of disassembling and assembling in the constructionprocess, the assembled temporary lengthening auxiliary structure 212includes a plurality of attachable sub-units, the length of eachsub-unit is determined by the distance that each track segment offsetfrom its adjacent track segment, as shown in FIGS. 9-10, the length ofthe sub-units is L1 and L2, respectively. The connection between thesub-units is shown in FIG. 9 and FIG. 10. Further, in at least oneembodiment, chord members and web members 213 arranged on the assembledtemporary lengthening auxiliary structure 212 as required are mounted byhigh-strength bolts. In addition, sliders 91 are arranged on the firstmain truss/beam 21 and the assembled temporary lengthening auxiliarystructure 212 at positions that engage with the track segments 61, 62and 63, as shown in FIG. 8.

2. As shown in FIGS. 3-4, the first set of hydraulic thrusters 71controlled by a computer control system is used to push the first maintruss/beam 21 into an appropriate position, the second main truss/beam22 and the corresponding assembled temporary lengthening auxiliarystructure 212 are installed on the assembly platform 8, then a set ofsecondary truss/beam 31 could be installed to connect the first maintruss/beam and the second main truss/beam to form a stable whole, asshown in FIG. 4. Upon completion of the above operation, the second setof hydraulic thrusters 72 is installed.

3. The sets of hydraulic thrusters 71, 72 controlled by the computercontrol system is employed to push the first sliding section to advanceuntil the first main truss/beam 21 reaches an overlap portion of twoadjacent track segments, which is shown as the overlap portion of tracksegments 63 and 62 in FIG. 5.

4. Then the first set of hydraulic thrusters 71 could be removed fromthe track segments 63 and installed at the track segments 62; and thesub-unit of length L2 of the assembled temporary lengthening auxiliarystructure 212 for sliding on the track segments 63 could be removed.Afterwards, the first sliding section is pushed forward by the sets ofhydraulic thrusters 71 and 72 controlled by the computer control system,and the track-changing process of the first main truss/beam 21 iscompleted by through the sliders 91 arranged on the first maintruss/beam 21, as shown in FIG. 6.

As mentioned above, the overlap is long enough for removing thehydraulic thrusters from prior track segments and installing thehydraulic thrusters on the subsequent track segments. To facilitate thetrack-changing process, the prior track segments and the subsequenttrack segments could be provided with export free cuts and import freecuts, respectively, to facilitate detaching the slider 91 from the tracksegments 63 and engaging with the track segments 62.

(6) Accumulative sliding is implemented. The second main truss/beam isassembled on the assembly platform 8 and then it is connected with thefirst sliding main truss/beam by the secondary truss/beam therebetweenaccording to design requirements to form a whole, after that respectiveset of hydraulic thrusters could be arranged. With reference to themethod of substeps 3 and 4 of step (5), the assembly process and thetrack-changing sliding for the second and third sliding trusses/beamsare sequentially completed. The fourth main truss/beam 24 is installedwhen all three sliding sections are in position, and the installation ofthe whole structure is completed, as shown in FIG. 7.

In the present embodiment, as shown in FIG. 11, before the first maintruss/beam 21 is pushed to slide, an assembled temporary auxiliarydevice for anti-overturning 13 is arranged at the front and rear of themain truss/beam 21 in sliding direction. The assembled temporaryauxiliary device for anti-overturning 13 is formed by weldingstabilizing rods 131 and columns 132, which may be formed by sectionsteel or steel plate. The stabilizer rod 131 includes a web plate at theend that is temporarily fixed to the connecting plate 141 or 142arranged on the lower chord 212 of the main truss/beam through bolts.The assembled temporary auxiliary device for anti-overturning 13 issupported on the sliding rail 6 n, and the distance L from the centerline of the columns 132 to the center line of the main truss/beam 21 isnot supposed to be less than 0.5 times the height H of the cross sectionof the main truss/beam 21. At least one slider 91 is arranged betweenthe columns 132 and the track segments 63 to ensure a smooth sliding,and the sliders 91 may be formed by the steel key block or by weldedsteel plate.

After the first main truss/beam 21 and the second main truss/beam 22 areintegrally connected, the assembled temporary auxiliary device foranti-overturning 13 arranged for the first main truss/beam 21 can beremoved.

As shown in FIG. 11, one end of each of the hydraulic thrusters 71 isfixed to the connecting plate 142 arranged on the lower chord 212 of themain truss/beam by one or more pin shafts, and the other end isconnected to a pushing base 12 at the other end through one or more pinshafts. The pushing base 12 formed by welded steel plates is supportedon side dams 18 located on both sides of the sliding track duringoperation of the hydraulic thrusters 71. In the present embodiment, thetrack segments is preferably made of channel steel, as shown in FIGS. 11and 12, wherein FIG. 12 is a sectional view of FIG. 11 taken along B-B.Side dams 18 are arranged on both sides of the track segments indirection along the length of the track by welding, and the spacing ofthe side dams 18 is matched with the stroke of the hydraulic thrusters.

FIG. 11 shows a detailed view of the support of the first maintruss/beam during sliding, wherein the track segment 63 is fixed to thetrack beam 17 and at least one slider 91 is provided between the lowerchord 212 of the main truss/beam and the track segment 63. The trackbeam 17 is supported on the track beam supporting structure 4, which isfixedly connected with the structural columns 1.

The structure of the slider 91 is shown in detail in FIG. 13, which isformed by welding an upper cover plate 19, a lower cover plate 20 and aweb plate 21, wherein the lower cover plate 20 is shaped as sledge bybending upwards with a radius R in the sliding direction. The slider 91is connected to the lower chord of the sliding structure by connectingparts 22, which is formed by welding at least one end plate 221 andL-shaped clamping plate 222. The end plate 221 is connected with theupper cover plate 19 of the slider 91 through bolts 23, and the clampingplate 222 is clamped with the lower flange of the lower chord of thesliding structure, as shown in FIG. 14.

1. Embodiment 2

Embodiment 2 of the present application is shown in FIGS. 15-23.

When the unequal-span roof or floor structure in the first embodimentshown in the FIG. 1 is constructed by sliding from the small-span sideto the large-span side of the structure, the method comprises thefollowing steps.

(1) The sliding track is designed and arranged. As shown in FIG. 15, thedesign of the sliding track is the same as that of the first embodiment,but since the sliding direction is reversed, the track segments thereofand the sliders 91 are numbered in reverse order.

The track segments, the track beam, the track beam support structure,the sliders 91, and the connection between the sliders 91 and thesliding main trusses/beams are same as those in the first embodiment, asshown in FIGS. 11-14.

(2) Based on the analysis of the whole process of accumulative sliding,the weight of the sliding structure and the track layout, thespecification, quantity and layout of the sliding hydraulic thrusters71, 72, 73 and 74 are determined, as shown in FIG. 15.

(3) The track segments and assembly platform are installed. As shown inFIG. 16, the track beam 17, the track beam supporting structure 4 andthe track segments 61, 62 and 63 are installed according to the designof step (1), and an assembly platform 8 used to assemble the slidingstructure is mounted to the sliding track at the end with smaller trackgauge. The sliding structure could be assembled and pushed off theassembly platform 8 section by section, such that each sliding sectioncould be assembled and slid from the assembly platform to the other endof the sliding track.

(4) The first main truss/beam is pushed to slide initially.

1. Initial sliding is prepared. The first main truss/beam 24 is dividedinto an initial sliding unit 24 a and rear-mounted units. The span ofinitial sliding unit 24 a matches the track gauge of the track segments63. The rear-mounted unit is divided into a plurality of sub-units, thelength of each sub-unit is determined by the differential between thetrack gauges of two adjacent track segments, as shown in FIG. 21, thelength of the rear-mounted sub-units is L1 and L2, respectively. Theinitial sliding unit 24 a and corresponding sliders 91 are assembled onthe assembly platform 8, as shown in FIG. 16.

2. The assembled temporary auxiliary device for anti-overturning 13 andthe first set of hydraulic thruster 71 are arranged at the front andrear of the initial sliding unit 24 a in its sliding direction, as shownin FIG. 11 of the first embodiment. After the above preparation work,the first set of hydraulic thrusters 71 is controlled by the computercontrol system to push the initial sliding unit 24 a of the first maintruss/beam 24 to slide.

(5) The track-changing process for each sliding section is performed.The sliding process of each sliding section is analyzed and the tracksthat each sliding section successively slides through are determined,then the sliders 91 could be arranged at corresponding positions of theinitial sliding unit 24 a and the rear-mounted unit for track-changingbetween track segments with different track gauges. Taking the firstsliding main truss/beam 24 as an example:

1. The first main truss/beam 24, which is of the largest span length,needs to slide through all three track segments 63, 62 and 61 insequence. As shown in FIG. 16, the span of the first main truss/beam 24is larger than the track gauges of the track segments 63 and 62,therefore the first main truss/beam 24 is divided into the initialsliding unit 24 a and the rear-mounted units, which is shown in FIG. 21and substep 1 of step (4), to enable the first main truss/beam 24 toslide through the track segments 63 and 62.

2. The initial sliding unit 24 a is assembled on the assembly platform 8together with corresponding sliders 91 and the first set of hydraulicthrusters 71, as shown in FIG. 16. The first set of hydraulic thrusters71 is controlled by the computer control system to push the initialsliding unit 24 a of the first main truss/beam to move to an appropriateposition, allowing the initial sliding unit 23 a of the second maintruss/beam and corresponding sliders 91 to be assembled and installed onthe assembly platform 8, then one or more secondary trusses/beams 33 areconnected between the first main truss/beam and the second maintruss/beam to form into a stable whole, as shown in FIG. 17. Uponcompletion of the above operation, the second set of hydraulic thrusters72 could be installed and the assembled temporary auxiliary device foranti-overturning 13 for the first initial sliding unit 24 a could beremoved.

3. The sets of hydraulic thrusters 71 and 72 is controlled by thecomputer control system to push the sliding section containing theinitial sliding unit 24 a forward until the initial sliding unit 24 areaches the overlap portion of the track segments, which is shown as theoverlap portion of track segments 63 and 62 in FIG. 18.

4. Rear-mounted units 24 b with length of L1, which is corresponding tothe track gauge between the track segments 62 and the track segments 63,are assembled at both ends of the initial sliding unit 24 a. The firstset of hydraulic thrusters 71 is removed from the track segments 63 andinstalled at the track segments 62, as shown in FIG. 19. Then the setsof hydraulic thrusters 71 and 72 could be controlled by the computercontrol system to push the sliding section forward further that is thesliding could be continued after the track-changing. The rear-mountedunit may be installed in high-altitude spread operation.

Preferably, the sub-units 24B and 24C of the rear-mounted unit may bepre-connected to the initial sliding unit 24 a by dedicated hinges 27,when sliding through a track segments with smaller track gauges, thesubunits could be folded, as shown in FIG. 22, to reduce beingobstructed. The sub-units 24 b, 24 c could be unfolded successively bymeans of the dedicated hinge 27, as the sliding structure reaches tracksegments with wider track gauges to engage with corresponding tracksegments, as shown in FIG. 23.

The overlap is long enough for removing the hydraulic thrusters fromprior track segments and installing the hydraulic thrusters on thesubsequent track segments. To facilitate the track-changing process, theprior track segments and the subsequent track segments could be providedwith export free cuts and import free cuts, respectively, to facilitatedetaching the slider 91 from the track segments 63 and to engage withthe track segments 62.

(6) Accumulative sliding is implemented. The second sliding maintruss/beam is assembled on the assembly platform 8 and then it isconnected with the first sliding main truss/beam by the secondarytruss/beam therebetween according to design requirements to form awhole, after that respective set of hydraulic thrusters could bearranged. With reference to the method of substeps 3 and 4 of step (5),the assembly process and the track-changing sliding for the second andthird sliding trusses/beams could be sequentially completed. The fourthsliding main truss/beam 21 could be installed when all three slidingsections are in position, and the installation of the whole structure iscompleted, as shown in FIG. 20.

The above embodiments describe the sliding construction for unequal-spanstructure comprising four main trusses/beams with different spans andthree sets of secondary trusses/beams. In actual construction, themethod can be applied to sliding construction for unequal-span structureincluding different numbers of main trusses/beams with different spans.For example, for the unequal-span structure whose number of maintrusses/beams with different spans is n, to apply sliding constructionaccording to the present application, the number of track segments couldbe n−1, and the number of hydraulic thrusters, etc. could be n.

1. An accumulative sliding construction method of segmentaltrack-changing for unequal-span structure, the unequal-span structureincludes at least three main trusses/beams with different spans, whereinthe construction method comprises the following steps: Step 1, designinga sliding track; dividing the unequal-span structure into at least twosliding sections and an individual truss/beam according to structuralspan variation, wherein each sliding section comprises a sliding maintruss/beam and a set of secondary trusses/beams connected; the slidingtrack is designed into a plurality of parallel track segments, thenumber of the track segments is equal to the number of the slidingsections, each track segment is offset from the adjacent track segmentby a certain distance, and the certain distance is respectivelycorresponding to the span differentials between every two adjacent maintrusses/beams; Step 2, analyzing the sliding process of the unequal-spanstructure; the weight of the sliding structure and the track layout, thespecification, quantity and layout of the sliding hydraulic thrustersare determined; Step 3, installing the track segments and an assemblyplatform; the track segments are arranged according to the design ofstep 1, and the assembly platform used to assemble the structure ismounted to a first track segment where the sliding process begins,wherein the first track segment extends onto the assembly platform; Step4, sliding process begins; a first main truss/beam is assembled on theassembly platform, and pushed away from the assembly platform by a setof hydraulic thrusters, wherein at least one assembled temporaryauxiliary device for anti-overturning is arranged for preventing thefirst main truss/beam from overturning during the sliding process; afterthe first main truss/beam leaving the assembly platform, a second maintruss/beam is assembled on the assembly platform, and at least one setof secondary trusses/beams is connected between the first maintruss/beam and the second main truss/beam to form a first slidingsection, then the assembled temporary auxiliary device foranti-overturning is detached; Step 5, track-changing process; pushingthe sliding section and the second main truss/beam in Step 4 forward bythe hydraulic thrusters until the first main truss/beam reaches aposition where the first track segment and its adjacent track segment, asecond track segment overlaps; each main truss/beam is provided with atleast one slider at positions corresponding to track gauges of the tracksegments that the main truss/beam slides through, ensuring the maintruss/beam leaves the first track segment and slides on the second tracksegment to perform a track-changing process; after the engagement of thesliders on the main truss/beam and the second track segment, the sliderscorresponding to the first track segments are removed for subsequentinstallation and sliding of the other main truss/beam; Step 6,accumulative sliding is implemented; assembling the subsequent maintruss/beam on the assembly platform, connecting it to the prior maintruss/beam by the secondary trusses/beams therebetween to form a slidingsection, arranging the corresponding set of hydraulic thrusters to pushthe assembled sliding section to move forward, and repeating the work ofthe step 5 until the installation of the whole unequal-span structure iscompleted.
 2. The method of claim 1, wherein the span of the maintruss/beam is smaller than the track gauge of the track segment whichthe main truss/beam engages with, and both ends of main truss/beam areattached with assembled temporary lengthening auxiliary structures. 3.The method of claim 2, wherein the assembled temporary lengtheningauxiliary structure includes a plurality of sub-units, the length ofeach sub-unit is determined by the differential between the track gaugesof two adjacent track segments of the track segments.
 4. The method ofclaim 3, wherein as the sliding main truss/beam passes one of the tracksegments, the sub-units corresponding to the one of the track segmentsare removed.
 5. The method of claim 1, wherein the span of the maintruss/beam is larger than the track gauge of the track segment that themain truss/beam engages with, and the main truss/beam is divided into aninitial sliding unit and rear-mounted units that are installed at bothends of the initial sliding unit, wherein the span of the initialsliding unit is equal to the track gauge of the track segment.
 6. Themethod of claim 5, wherein the rear-mounted units comprise a pluralityof sub-units, and the length of each sub-unit corresponds to thedifferences in track gauges of two adjacent track segments of the tracksegments.
 7. The method of claim 6, wherein as the sliding maintruss/beam passes one of the track segments, the sub-units correspondingto the next one of the track segments are mounted.
 8. The method ofclaim 6, wherein folding hinges are used for mounting the rear-mountedunit to the initial unit, as well as connection between sub-units of therear-mounted units, and as the sliding main truss/beam passes one of thetrack segments, the sub-units corresponding to the next one of the tracksegments are unfolded.
 9. The method of claim 3, wherein the connectionsbetween the main truss/beam and the assembled temporary lengtheningauxiliary structure, the connections between the initial sliding unitand the rear-mounted unit, the connections between the sub-units of theassembled temporary lengthening auxiliary structure, and the connectionsbetween the sub-units of the rear-mounted unit are formed by channelsteels and high strength bolts.
 10. (canceled)
 11. The method of claim5, wherein the connections between the main truss/beam and the assembledtemporary lengthening auxiliary structure, the connections between theinitial sliding unit and the rear-mounted unit, the connections betweenthe sub-units of the assembled temporary lengthening auxiliarystructure, and the connections between the sub-units of the rear-mountedunit are formed by channel steels and high strength bolts.